I know how the difficulty works, but RIGHT NOW those are the stats and I'm proposing that RIGHT NOW that is why the price is tanking. If the hash rate drops an appreciable amount so that mining is significantly easier, don't you think that will drop the value of the coin too?
Masternodes are subject to exactly the same economics as mining - the more there are the less the gain. It isn't a question whether it "works" or not, it's just another way people can service the network and receive compensation for doing so.
As you said yourself, this is the situation *now*, but it will be in a constant state of flux. More miners - difficulty goes up, revenue per hash goes down. More masternodes - network service sector increases, revenue per node goes down.
Ann additional dynamic is that while mining increases the money supply, masternodes *decrease* it and the net effect of this is to increase the price for both holders and miners.
Sidenote: OUCH. My VeniVidiVicci has tanked to a quarter of its value. I didn't enjoy that. (+ didn't offload my XC fast enough after the pump and now can't get rid of it).